<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>31_节点操作</title>
    <link rel="stylesheet" href="./css/basic.css">
    <style>
        .container {
            width: 100%;
            height: 100vh;
            background-color: pink;
            padding: 10px;
            box-sizing: border-box;
        }
        
        .content {
            width: 100%;
            height: 75%;
            background-color: #fff;
            padding: 20px;
            box-sizing: border-box;
        }
        
        .input {
            height: 20%;
            width: 100%;
            position: relative;
            margin-top: 20px;
        }
        
        .input textarea,
        .input button {
            position: absolute;
            resize: none;
        }
        
        .input textarea {
            width: 100%;
            height: 100%;
            padding: 10px;
            box-sizing: border-box;
        }
        
        .input button {
            right: 10px;
            bottom: 10px;
            width: 100px;
            height: 50px;
            background-color: blue;
            color: #fff;
            font-size: 20px
        }
        
        .message {
            color: brown;
            font-weight: bolder;
            font-size: 30px;
            margin-right: 20px;
        }
        
        .datetime {
            color: #000;
            font-size: 12px;
        }
    </style>
</head>

<body>
    <div class="container">
        <!-- 聊天区 -->
        <div class="content"></div>
        <!-- 输入区 -->
        <div class="input">
            <textarea name="" id="contentArea"></textarea>
            <button id="btnSend">发送</button>
        </div>
    </div>
    <script>
        const btnDom = document.querySelector("#btnSend") // 发送按钮对象
        const textareaDom = document.querySelector("#contentArea") // 输入区对象
        const contentDom = document.querySelector(".content") // 聊天区对象
        enableBtn()
        textareaDom.addEventListener("input", (event) => {
            enableBtn() // 控制按钮是否能点击
        })
        btnDom.addEventListener("click", () => {
            sendMsg()
        })

        textareaDom.addEventListener("keydown", (event) => {
            if (event.key === "Enter") {
                sendMsg()
            }
        })

        function enableBtn() {
            if (textareaDom.value) {
                // 删除disabled属性
                btnDom.removeAttribute("disabled")
            } else {
                // 加上属性
                btnDom.setAttribute("disabled", true)
            }
        }
        // 发送消息
        function sendMsg() {
            // if(textareaDom.value)
            const content = textareaDom.value // 聊天的信息
                //    contentDom.append()
            const p = document.createElement("p")
            p.innerHTML = `<span  class='message'>${content}</span><span class='datetime'>${new Date().toLocaleString()}</span>`

            contentDom.append(p)
            textareaDom.value = ""
        }
    </script>
</body>

</html>